Furnace for treating refractory ores containing precious metals



- l l y 927 G. W.'B. EVANS FURNACE FOR TREATING REFRACTORY ORESCONTAINING PRECIOUS METALS Filed Aug. 15. 1926 IfnvenZ'Ez Patented July19, 1927.

UNITED STATES GEORGE B. EVANS, OF WILDERNESS, VIRGINIA,

PATENT OFFICE;

ASSIGNOR TO EVAN S ORE REDUC- TION COMPANY, OF WASHINGTON, DISTRICT OFCOLUMBIA.

FURNACE FOR TIPEATING REFRACTORY ORES CONTAINING PRECIOUS METALS.

Application filed August 13, 1928. Serial No. 128,983.

of a furnace f or treating refractory ores containing precious metals.

The object of In invention is to roduce amachine or urnace which treatsthe ores more perfectly than has ever been done heretofore and at thesame time recover more values than has been done by any method )reviousto my invention, a fact established 'y an experimental plant now inoperation.

A further object of my invention is to produce a furnace which recoversthe vahicsin an economical manner and does not allow the metals toescape when the same become volatile, as has been the case in otherprocesses and machines or furnaces for treating such ores.

Reference is made to the accompanying drawings which form a part ofthese specifications, in which; Figure l-is a sectional elevation of myinvention, Figure 2 is a detailed .view showing a cover plate for theopening throu h which ore is inserted into the inner-revolving cylinder,andFigure? is a detailed view showing one manner of. supporting therevolving cylinder on the drive shaft and the means for conveyinghydrogen gas into said revolving cylinder.

Like characters of reference designate corresponding parts in theseveralfigures of the drawing.

- My furnace consists of a cylindrical cham- My invention consists her,1 with an opening 2 closed by a cover 3,

said covcr being substantially airtight when closed, the. opening 2allowing access to the inside of the cylindrical chamber 1. The cylinder1 is supported by ends 4 and 4 shown as heavy castings on the drawing,but other forms of ends may be used without departing from the spirit ofmy invention.

The ends 4 and 4. support bearings 5 and 6 respectively for a horizontalshaft 7 which passes through the furnace and is driven by a pulley orsprocket wheel secured to the end of'shaft 7 from any suitable power.

Stuffing boxes 13 are arranged around the shaft 7 in the ends 4 and 4 toprevent the escape of gases hereinafter mentioned from the cylinder 1.Surrounding the cylinder 1 is a combustionchamber .15 and a firebox l6beneath the cylinder which forms a part of the, combustion chamber. Astack is arranged at the top and to the rear of the urnace to allow ofthe escape of the particles ion application in that of combustion.Surroundingsaid firebox is a wall composed of non-heat conductingmaterial, such as firebrick or the like 18, to retain as much of theheat within the furnace as is possible. v

A supply pipe 19 is carried through the outer wall of the furnace whereit connects with a pairof heating coils 20 and 21 arranged directly overthe fire, for heating and superheating the which is to be conducted fromsaid coils through a suitable pipe-line 22, provided with a controlvalve 23 into the cylindrical chamber 1, and into a revolvingcylindrical chamber within said chamber 1 hereinafter mentioned.

p The cylindrical chamber .1 is rovid'ed with an opening 24 in'the lowersi e of the forward end thereof, said opening bein by a suitable door25, secured by van. ocking bar-26 engaging a pair of wed ed lugs Thedoor is provided with beve fit against similar surfaces around theopening in order to insure a. tight fit to prevent the escape of gas.

from the cylinder 1 diagrammatically pipe 28 is to allow the escapeof'excessive contained in the plate 4 of the furnace is provided with anopening closed by a suitable door 31 through which fuel is fed to thefirebox. A door 32 to condensers 29 shown in the drawings.

gas or gases An outlet pipe 28 leads The provided with a'release valve30 ed edges to cylinder 1. The front end directlybeneaththe door 31 butsecured to i the foundation of the furnace is provided for the removalof ash from the pit beneath the firebox. i I

The entire furnace including the cylindrical chamber 1, the end plates.4 and 4 and the surrounding wall 18, is held together by a plurality oftie-rods 33 having nuts 34 at the ends thereof and'bearing against theouter surfaces of the end plates 4 andA, The outer wall of thefurnace'is supported and reinforced by a plurality of T irons, and

the furnace is-inounted upon a masonry or concrete foundation 42 asshown.

The construction --above described and shown 18 substantially the sameas a companion case filed by me and bearing an even filing date withthis application.

This application differs from the compans the lifters described in saidcompanion application are dispensed with and the followingconstruction.- emcover 54 secured by latch bolts 55 which may bodied inlieu thereof, although the operation and the results obtained are thesame in both applications,

' Mounted within the cylinder 1 and free to rotate therein is a cylinder50 secured to the shaft 7 by arms 51 of spiders 52 mounted upon saidshaft. The cylinder 50 is provided with an opening 53 through which oremay be fed into said cylinder by placing a funnel or chute down throughthe opening 2 leading to the cylinder 1. The opening 53 has a be easily0 erated by a socket wrench extended down t rough the opening 2. Aneyelet 56 is secured to the cover 54 for the urpose of quickly removingsaid cover w ien de- I sirous of filling the cylinder 50 with a chargeof ore to he treated.

An opening 57 is provided in one end of the cylinder 50 in order that itmay be brought opposite the opening 24 for the purpose of removin thecharge of ore within the cylinder 50 a ter the same has been treated.The opening 57 is closed by a cover which is secured in a manner similarto that for lockin the cover 54 in place. t is not necessary-norintended that the cylinder 50 be air and gas tight as is the cyllndiicalchamber 1, but the openings leading into said chamber must be securelyclosed in order that ore will not spill out and interfere with therotation of said inner cylinder 50. Arranged within the cylindricalchamber 50 are a series of liftin plates 58 extending the entire lengtht ereof and secured at their ends to the inner walls of the end platesof said cylindrical chamber. The plates 58 are provided with upturnedinner edges 59 which act in the same capacity for holding the ore beinglifted as do the upturned flanges of the lifters in my companionapplication. v

' While I have shown a spider form of con struction for securing thecylinder 50 and its lifting plates to the shaft 7 I may use some othermethod of securing the cylinder 50 to the shaft 7 as well as anynecessary means for properly strengthening the cylinder and its plateswithout departing from the spirit of my invention.

Hydrogen gas heated and superheated by the system of coils, or return.pipes 20 and 21 is fed under pressure into the cylindrical chamber 50bythe pipe 22 which is controlled by a valve 23 as shown on the drawing.The pipe 22 is brought through the outer end wall a of the furnaceadjacent to the shaft 7. The rear end Wall 60 of the cylindei. 50 isprovided with an opening 61 sprrounding the shaft 7 to accommodate thepipe 22as it projects within the cylinder 50. A bafilc plate 62 isprovided around the shaft 7 in order to disperse the hydrogen gas as itcomes from the pipe 22. The baffle plate 62 performs an additionalfunction of aces,

rotating chamber, means preventing the ore which is being treated withinsaid cylinder from clogging up the end of the pipe 22. y

The operation of my invention is as follows:

Pulverized refractory ore is mixed with certain chemicals mentioned in aprocess application filed even date herewith, by myself, is introducedinto the inner revolving cylinder 50 through the openings 2 and 53,after which said openings are closed by the covers 3 and 54:respectively. Intense heat is applied to the outer surfaces of thecylinder 1, said heat radiating to and into the inner cylinder 50. Assoon as the heat has arisen toa suiiiciently high temperature the valveair journey up ore which has fallen to the bottom and lift or carry itto the top as before. This 'ves me a continuous flow of the ore througthe gases contained within the cylinder.-

The chemicals above mentioned due to the intense heat surrounding thecylinder 1 are converted. into gases which, to ether with the hydrogengas introduced through the pipe 22, throroughly impregnate everyparticle of the ore as it is falling off the lifting plates, and after apredetermined time separate the precious metals from the baser metals ofthe ore. Some metals, as has been found by experiment,-become volatile,and these metals pass ofi through the opening 61 to the cylindricalchamber 1 and from thence to the condenser or condensers :29 where theymay be recovered.

Having thus described my invention, what I claim is: p I

1. In a stationary furnace designed for the purpose of treatingrefractory ores containing precious metals, an airtight chamber, meansfor admitting hydrogen gas int-o said chamber, an inner rotatingcylindrical chamber, means for admitting hydrogen gas into said innerchamber, means for admitting ore into said inner rotating chamber,

2. In a stationary furnace designed for the purpose of treatingrefractory ores containing precious meta s, a. cylindrical airtightchamber, an inner rotating chamber, means for admitting hydrogen gasinto said inner for admitting ore into said inner chamber, means for,lifting said ore, and dropping the same in the form or spray, means forrelieving excess ve gas pressure in the stationary chamber, and

means for extracting the treated ore 'from the .inner rotating chambersubstantially as Shown.

A stationary furnace designed for the purpose of treatin refractory orescontaining precious meta s, a fixed airtight chamher, an inner rotatingreceptacle, and means for applying heat externally to the fixed chambersubstantially asishown.

4. In a stationary furnace designed for the purpose of treatingrefractory ores containing precious metals, a fixedhorizontaLcvlindrical chamber, an inner rotating cylindrical receptacle,means for admitting hydrogen gas into said inner receptacle, means forinserting ore into said inner receptacle, means for lifting and droppingsaid ore in the form of spray within said inner receptacle, means forsuppyling heat externally to the fixed cylinder, and means forextractingthe ore from the inner receptacle substantially as shown.

In testimony whereof I hereby affix my signature.

GEORGE W. nxnvans.

